Alkylated indanols as deterioration retarders for rubbers



ALKYLATED INDANOLS AS DE'IERIORATION RETARDERS FOR RUBBERS Roger E.Morris, Cuyahoga Falls, Ohio, assignor to The B. F. Goodrich Company,New York, N.Y., a corporation of New York No Drawing. Filed Sept. 10,1956, Ser. No. 608,699

*6 Claims. 01. 260-4535) This invention relates to the preservation andprotection of organic materials subject to deterioration on aging and/or in service, and more particularly to the preservation and protectionof rubber and rubber products, by the incorporation into such materialsand products of one or more of a new class of chemical compounds.

The new class of chemicals comprises the reaction products of an indanolor a substituted indanol with an olefin, which reaction products aresometimes herein for convenience referred to as alkylated indanols andwhich reaction products applicant has discovered to function asextremely effective deterioration retarders for organic materials andespecially for rubber and rubber products.

In vulcanized rubber products subjected in service to continuous flexingand/ or to heat, as for example, a rubber tire, either pneumatic orsolid, and a rubber belt, especially a belt operating on small pulleysand/or at high speeds, the new class of chemicals of this invention hasbeen found to impart to the vulcanized rubber remarkably highanti-flex-cracking properties and excellent heat stabilizing properties,as well as extremely effective resistance to loss of tensile strength,elongation and other desirable properties of newly vulcanized rubberproducts. The deterioration retarders of this application are,furthermore, non-staining and non-discoloring, and hence areparticularly well adapted for use in white or light rubber stocks, andare outstanding when used in White sidewall stocks of automobile tiresand in the rubber stocks contiguous to the white sidewalls.

The indanols utilized as starting reactants in the production of thealkylated indanol deterioration retarders of this application are of thegeneral formula Ila/2 3 5 2 R2 1 I 7 Rm 1 wherein the OH group isattached to a carbon atom of the phenyl ring of the indan group ineither the 4- or the 5-position, on in either the 7- or the 6-position;each of the carbon atoms of the phenyl ring which has a replaceablehydrogen atom attached thereto and is positioned ortho or para to thecarbon'atom to which the OH group is attached being a carbon atom in anopen reactive position; R represents a monovalent substituent selectedfrom the class consisting of hydrogen and alkyl and aral'kyl radicalshaving from 1 to 8 carbon atoms; In is l; and R represents a monovalentsubstituent selected from the class consisting of hydrogen and alkylradicals having from 1 to 8 carbon atoms, each R attached to the indangroup in the divalent 1-, 2- and 3-positions, and each R and Rrepresenting the same or a different monovalent substituent.

and

is an indan group, from which structures it will be noted that the 4-and 7-p0sitions and the 5- and 6-positions are corresponding positions.In order to simplify the description herein, reference will be madeherein only to the a structure, with the understanding that thedescription applies equally as well to the 1) structure, and 4-hydroxyindan and S-hydroxy indan (also referred to as 4-indanol and S-indanol)include 7-hydroxy indan and 6-hydroxy indan (7-indanol and 6-indanol),respectively.

In the indanols of above Formula 1, m may be 0 or 1. Where In is 0,there are two open reactive carbon atoms in the phenyl ring, ortho and/or para to the OH group. Thus, where the OH group is attached to acarbon atom in the 4-position, the carbon atoms in the ortho S-positionand in the para 7-position are open reactive carbon atoms, and makepossible the attachment of an olefin group in either the 5-position orthe 7-position, or both. Similarly, where the OH group is attached to acarbon atom in the 5-position, the carbon atoms in the ortho 4- pcsitionand in the ortho 6-position are open reactive carbon atoms, and makepossible the attachment of an olefin group in either the 4-position orinthe 6-position, or both, with the 6-position being more highlyreactive. However, where m is 1, the radical R is attached to one of thetwo open reactive carbon atoms in the phenyl ring, all as above setforth, leaving the other reactive carbon atom open for the attachment ofthe olefin group.

The indanols which have been found to be preferred as starting compoundsin the production of the deterioration retarders of this application arethose in which the OH group is attached to a carbon atom of the indangroup in either the 4- or the 5-position and include both theunsubstituted indanols, such as 4-ind'anol and S-indanol, in which, inFormula 1 above, m is zero and each R is a hydrogen atom, and also thesubstituted indanols in which, in Formula 1 above, m may be 1 and/oroneor more of the six Rs may be radicals within the scope of R and theremaining R's, if any, hydrogen'atoms. "The following three classes ofindanols are hereinbelow noted:

(a) Among the indanols of the general Formula 1 in which m is 0 and eachR is a hydrogen'atom, and which are useful as starting reactants in theproduction of the deterioration retarders of this invention are4-indanol and S-indanol.

(12) Among the indanols of the general Formula 1 above, in which m is land each R is a hydrogen atom, and which are useful as startingreactants in producing the deterioration retarders of this invention,are, to enumerate certain typical examples, the following:5-methyl-4-indanol, 7-rnethyl-4-indanol, 4-methyl-5-indanol, 6-methyl-S-indanol, and higher homologues including radicals within the abovedefinition of R, such as ethyl, the propyls, butyls, amyls, hexyls,heptyls, octyls, etc.

Among the indanols of the general Formula 1 above in which one or moreof the R's attached to carbon atoms in the 1-, 2- and/or 3-positions ofthe indan group are radicals within the definition of R above, and whichare useful as starting reactants in the production of the deteriorationretarders of this invention are 1- methyl 4-indanol,1,1-dimethyl-4-indanol, 1,3-dirnethyl- 4 indanol, 1,1,3trimethyl-4-indanol, 1,1,5-trimethyl-4- indanol, 1,1,7trimethyl-4-indanol, 1,l,3,5-tetramethyl-4- indanol,1,1,3,7-tetramethyl-4-indanol, 1,1-dimethyl-3-isopropyl 4 indanol,1,1-dimethyl-3-ispropyl-5-t-butyl-4- indanol, l-methyl 5 indanol,1,1-dimethyl-5-indanol, 1,3-dimethyl 5 indanol,1,1,3-trimethyl-5-indanol, 1,1,4- trimethyl 5 iudanol,1,1,6-trimethyl-5-indanol, l,l,3,4- tetramethyl 5 indanol,1,1,3,6-tetramethyl-5-indanol, 1,1-dimethyl-3-isopropyl 5 indanol,1,1-dimethyl-3-isopropyl 4 t butyl-S-indanol, and similar higherhomologues, such as ethyl, the propyls, butyls, amyls, hexyls, heptyls,octyls, etc.

The hydrocarbon substituted indanols indicated in the two precedingparagraphs (12) and (c) and similar hydrocarbon substituted indanols,are sometimes in the specification and in the claims of this applicationreferred to as alkyl indanols, using the term alkyl in a broad sense toinclude all hydrocarbon radicals Within the definition of R and R asabove set out.

It is to be understood that the above indicated indanols areillustrative only and are not to be considered in limita tion of theinvention of this application.

The olefins employed for alkylation," using this term in a broad sensecommonly employed in industry, are represented by the general formulaRI! wherein R" represents a monovalent substituent consisting ofhydrogen and a radical such as alkyl and aralkyl, having from 1 to 8carbon atoms, and may be any olefin of a natural or synthetic source, ormixtures thereof. Preferably an alpha-olefin is employed, such asethylene, the propylenes, diisopropylene, the butylenes, diisobutylene,and higher homologues thereof, as well as the cyclic-substitutedolefins, such as styrene, alpha-methyl styrene, and also alpha-olefinsobtained from the cracking of petroleum fractions.

The indanols of Formula 1 above and the olefins of Formula 3 above,according to the invention of this tip plication, react to producealkylated indanols of the following general formula:

Ra OH 5 /Rll R 2 0-0113 I 7 R" n Rm 4 wherein the OH, R, R and R and mhave the same significance as in Formulas 1 and 3 above, n represents aninteger either 1 or 2, and the sum of m and n is an integer from 1 to 2.

For convenience in the description in the specification and claims ofthis application, the

/RII C-CHa group is termed an alkylating group and its presence in acompound containing such group is termed an alkylated compound. By wayof illustration, the reaction of S-indanol and isobutylene, insubstantially molar proportions, normally produces6-t-butylated-5-indanol, and from the reaction of 1 mole of S-indanolwith 2 or more moles of isobutylene some 4,6-di-t-butylated-5-indanolmay be produced. Again, the reaction of 6-methyl-5-in- 4 danol withisobutylene normally yields 6-methyl-4-t-butylated-S-indanol or,expressed in an equivalent way, 4-tbutylated-6-methyl-5-indanol.

The alkylated indanols which have been found to be preferable asdeterioration retarders in the invention of this application are thosein which the OH group is attached to a carbon atom of the indan group ineither the 4 or the 5-position, and include both the reaction productsof olefins with unsubstituted indanols and the reaction products ofolefins with hydrocarbon substituted indanols of the characterhereinabove described.

In the reaction of an olefin with an unsubstituted 4- indanol, where, inthe resulting alkylated-4-indanols (see Formula 4 above) each R is ahydrogen atom and R is a radical within the definition of R above,herein termed alkyl using that term in a broad sense to include allbydrocarbon radicals within the definition of R, as explained above (1)Where m is zero and n is 1, the alkylated-4-indanols produced are5-alkylated-4-indanol, 7-alkylated-4-indanol;

(2) Where m is zero and n is 2, the alkylated-4-indanol produced is5,7-dialkylated-4-indanol; and

(3) Where m is 1 and n is 1, the alkylated-4-iudauol produced is7-alkyl-5-alkylated-4-indanol or 5-alkyl-7- alkylated-4-indanol.

Similarly, in the reaction of an olefin with an unsubstituted S-indanol,where in the resulting alkylated-S- indanols (see Formula 4 above) eachR is a hydrogen atom, and (4) Where m is zero and n is 1, thealkylated-S-indanol produced is G-aIkylated-S-indanol;

(5) Where m is zero and n is 2, the alkylated-S-indanol produced is4,6-dialkylated-5-indanol; and

(6) Where m is 1 and n is 1, the alkylated-S-indanol produced is6-a1kyl-4-alkylated-5-indanol or 4-alkyl-6- alkylated-S-indanol.

Where, in the resulting alkylated indanols (see Formula 4 above), any Ris not a hydrogen atom but a radical within the definition of R above,herein termed alkyl using that term in a broad sense to include allhydrocarbon radicals within the definition of R, as explained above withrespect to R, then each of the many alkylated indanols indicated abovemay have numerous distinct derivatives. Examples of the alkylderivatives of 5-alkylated-4-indanol of paragraph 1) above, in whichcertain of the R's are alkyl groups attached to carbon atoms in thebivalent 1-, 2- and/or 3-positions of the indan group, include1-alkyl-5-alkylated-4-indanol, 1,l-dialkyl-5-alky1ated-4-indanol,3-alkyl-S-alkylated-4-indanol, 3,3 dialky1-5-alkylated-4-indanol, 1,1,3-trialkyl-5-alkylated-4-indanol, 1,1,3,3 tetraalkyl-5-aJkylated-4indanol, and so on with the diflerent combinations of alkyl substitutesin the bivalent 1-, 2- and/or 3-positions of the indan group. Examplesof the 7-alkylated-4-indanols having alkyl groups in the 1-, 2- and3-positions, are 1,5- dialkyl-7 alkylated-4-indanol,1,1,5-trialkyl-7-alkylated- 4-indanol,1,1,3,5-tetraalkyl-7-alkylated-4-indanol, and so on with the manycombinations of R's in the bivalent 1-, 2- and/or 3-positions of theindan group. Examples of similar derivatives of 6-alkylated-5-indanol ofparagraph (4) above, include l-alkyl-6-alkylated-S-indanol,1,1-dialkly-6-alkylated-5-indanol, 3-alkyl-6-alkylated-5-indauol,3,3-dialkyl-6-aJkylated-S-indanol, 1,1,3-trialkyl 6 alkylated-S-indanol,1,l,3,3 tetraalkyl-6-alkylated-S-indanol; and so on with differentcombinations of alkyl substitutution in the bivalent 1-, 2- andiior3-positions of the indan group.

Examples of the alkyl derivatives of the 5,7-dialkylated- 4-indanol ofparagraph (2) above in which one or more of the Rs are alkyl groupsattached to one or more of the carbon atoms in the bivalent 1-, 2- and/or 3-positions include 1-alky1-5,7-dialkylated-4-indanol,1,l-dialkyl-5,7- dia1kylated-4-indanol, 1,1,3trialkyl-5,7-dialkylated-4-indanol, 11,1,3,3=tetraalkyl-5,7-dialkylated4-indanol, and so on with different combinations of alkyl substitutionin the bivalent -1--., 2- and'/or 3,-positions of-the indan group.Similarly, the alkyl derivatives of 4,6-dialkylated-5-indanol ofparagraph (5) above include 1-alkyl-4,6-dia]kylatedfi indanol, 1,1"-'dialkyl 4,6 --diailkylatedr5-indanol,1,1,3-trialkyl-4,6-dialkylated-5-indanol, 1,l,3,3-tetraalkyl-4,6-diailkylatede5 indanol, and 'so 'on with the different combinations:o-f a1kyl substitution in the bivalent 1-, 2- and/or -3-positions "ofthe indan group.

[Examples of "the :al-kyl derivatives of the 7-alkyl-5-alkylated=4-indanol of the paragraph (3) above include l-lalkylfl-alkyl5 alkylated-4 indanol, 1,1 -dialkyl-7-alkyl- 5ealkylat'ed 4=indanol,l,L,3-trialkyl-7-alky1-5 alkylated- 4 inr1ano'l, and so on with thedifferent combinations of alkyl' substitutioniin the bivalent 1-,'2-and/ or 3-positions of the imian groups. Similarly, examples of thealkyl derivatives "of the 6=alkyl 4=alkylated-SPindanol of theparagraph/(6) above include .l raIlkyl b-alkyl-4-alkylated- S-indanol,1,1-a]lcyl-6-alkyl-4-alky1ated-5-indano1, 1,1,3- trialkyl-7-alkyl-4-alkylated-5indanol, and so on with the differentcombinationsof alkyl'stibstitution in the bivalent 1-, 2- and/or3-positions of the indan group. Where all the alkyl groups in any of theabove named com- -pounds represent the same hydrocarbon radical, thealkyl groups may be written together thus': 1,1,3-trialkyl-7 alkyl-5alkylated-4 indahol may "be written 1,1,3,7-tetraalk yl 5 alkylated 4Findanol, or where each 7 alkyl group represents methyl and thealkylating olefin is isobutylene, the compound may be written1,1.,3,7-tetramethyl-5=t butylated-4-indanol. Again where'the "alkylgroups do not all represent the same hydrocarbon radical, as wheremethyl groups are attached to the carbon atom in the 1-position, anethyl group tothe carbon atom in the 3-position, "an oct-yl group to thecarbon atom in the 7-position and the alkylating olefin is isobutylene,the .-1,1,3,7-tetraalkyl-5-alkylated-4-indanol may be written 1,1--dimethyl-3-ethyl-7-octyl-5 t-butylated-4- indanol.

In carrying out the reactions between the above described indanols andolefins, a suitable catalyst is preferably employed. Satisfactoryresults have been obtained with such acidic condens-ationcatalysts assulfuric acid, p' toluene "sulfonic acid, boron trifluoride, acidactivated cla s, and 'he like. Particularly useful are combinations such"as sulfuric acid and finely-divided acid "activated clay. The use ofacid -activated clay -is particularly advantageous since the reactionmixture has only to be 'iiltered and the solvent removed'to be ready foruse. In addition, the acid activated clay removes many colored andotherwise undesirable reaction by-products.

The acid activated clays preferred are those whose maior component isaluminum silicate in an amount preferably -'greater than 50 percent. Theclay is preferably of such particle size that greater than 90 percent ofthe particles will pass 211325 mesh screen and have a particle size'1e'ss than0.()5 millimeter, although clays of coarser particle sizes"have been satisfactorily employed; "The acid activated clay preferablyhas an acid react-inner is acid treated, with a pH between 1 and 6. Sucha "clay is available "on the market as Retrol acid activated 'clay; The"amoun'tof clay employed may be from "0.510 H) Weight percent ofthereac'tants, or more. The amount of other acid catalysts utilized inthe reaction may be varied quite widely but is generally from 0.1 toabout 5.0 weight percent of the reactants, although from about 0.5 to 10weight percent may be employed.

The amount of the reaction product of this invention that may beefiectively employed in rubber compositions ranges from 0.3 to aboutlOweight'percent based on the rubber, whereas to obtain maximum value ofthe deterioration retarder an amount ranging from about 0.5 to 5 weightpercent on the rubber will .give satisfactory results.

The term rubber ise nployed in this application in a generic sense to:include all natural and synthetic unsaturate'd rubbery polymericmaterials. The term rubbery' diolefinic polymer is employed in thisapplication in a broad generic sense to include the variousnaturalrubbers, which are regarded as naturally occurring isoprene polymers,and such synthetic rubbers as polymers of conjugated dienes, such asbutadiene-l,3, isoprene, piperylene, chloroprene, cyano-butadiene-1,3,as well as copolymers of these conjugated dienes with each other, andalso copolymers of any of these conjugated dienes with other unsaturatedchemical compounds copolymerizable therewith such as styrene,chlorostyrene, isobutyiene, acrylonitrile, methacrylonitrile, acrylicand methacrylic acids, alkyl acrylates and methacrylates, vinylidenechloride, vinyl pyridines and the like.

In general, in the preparation of the reaction products of thisapplication, the reaction is carried out in any of the standard reactionvessels, since the temperatures and pressures employed are relativelylow and necessitate no special equipment. Preferably the reaction vesselis equipped with a thermometer, an 'agitator, areflux condenser ventingto the. atmosphere, an inlet tube for introducing fiuids into thebottornportion of the vessel and fior aliquid dropper for feeding liquidsdropwise int thevesse'l.

In general, the reaction of the indanols and the alpha: olefins iscarried out at substantially atmospheric pressures and at temperaturesranging from 25 to C. but it is to be understood that the temperaturesat which the reaction takes place are not critical.

EXAMPLE I A reaction vessel is equipped with a thermometer, agitator,reflux condenser and inlet tube for introducing gaseous olefins into thebottom of the vessel beneath the surface of'the liquids therein.

Thereaction vessel is charged with 268 g. (2 moles) of 'S-i'ndanol,40'0,milliliters of benzene and. 25 "g. of Retrol acid activated clay.The mixture is warmed to 55" C. and isobutylene is introduced through.the inlet tube beneath the "surface of the iiquid with agitation; Theis'obut'ylene is added as rapidly as' it'ist'aken up at 55 to 80 C.'over a period of about 3% hours. Addig tion is continued for some timeafter the uptake becomes very slow to secure a maximum yield, although.this is not necessary. The reaction mixture is then "suction filteredto remove the acid activated clay, and the filtrate is distilled toremove the benzene. The residue is dis tilled under reduced pressure togive 380, g. (87.1%).

yield) of 6*t-butylated-5 indanol, having a boiling point of 143 to 146C. at 9 mm, and 'a melting pointjof 74 to 765 C. An analysis of the endproductconfir'ms the chemical constitution to be that of6-t-buty1ated-5' indanolp v H 1 EXAMPLE II This example illustrates thepreparation oifthe t-butylat'ed-4-indanols and is carried out in theapparatus described in Example I. g

The reaction vessel is charged with '50 g. (0.375 mole) of 4-indanol,milliliters of benzene and 10 g. of Retrol acid activated clay.lsobutylene is introduced and 'the reaction carried out as described inExample I. The reaction mixture is suction filtered and the benzenedistilled oif. The distillation of the residue. under "reduced pressuregives two fractions; ('1) 15.9 g. of 'S-t-butylated-4-indanol having aboiling point of 132 to 143 C. at 6 mm. and a melting point of 49-.5 to57 C.; and (2) 43.9 g. of 5,7-di t-butylated-4-indanol having aboiling'poin't or '95 to 103 'C. at 0.3 mmf and .a melting point of 58to '61' 'C. An analysis of each of these products confirms its identity.

EXAMPLE III This example illustrates the production of "6-'octyla'ted-.S-indanol by reacting 5 -indan'ol 'With 'diisobu'tylehe.

The reaction is carried out in the apparatus described in Example I,except that a dropper is employed to introduce the diisobutylene.

The reaction vessel is charged with 134 g. (1 mole) of S-indanol, 250milliliters of glacial acetic acid and 5 milliliters of concentratedsulfuric acid. The vessel contents are warmed to 50 C. and 114 g. 1.1moles) of diisobutylene is added dropwise with agitation. During theapproximately two hour period the diisobutylene is being added, thereaction mixture is warmed to about 70 C. After heating the vesselcontents with agitation at from 70 to 90 C. for nine hours, the reactionmixture is poured into Water. Benzene is added and an organic layer isdecanted off, washed, dried and concentrated. The benzene and anyunreacted S-indanol is removed by distillation. The residue is distilledunder reduced pressure to yield 99 g. of 6-octylated-5-indanol having aboiling range of 87 to 107 C. at 0.3 mm., which is a colorless oil thatcrystallizes readily to give a waxy solid having a melting point of 49to 60 C. Analysis confirms the identity of the end product.

EXAMPLE IV The preparation of 6-alpha-methylbenzylated-S-indanol isaccomplished by the reaction of S-indanol and styrene, thus:

The reaction is carried out in the apparatus described in Example III.The reaction vessel is charged with 134 g. (1 mole) of S-indanol, 200milliliters of benzene and 20 g. of Retrol acid activated clay. Themixture is warmed to about 50 C. and styrene is added dropwise withstirring over a period of 45 minutes. Heating and stirring are continuedat near reflux temperatures for 2 hours. The vessel contents are suctionfiltered to remove the acid activated clay. The filtrate is distilled toremove the benzene and any surplus indanol. The residue is distilledunder reduced pressure. There is produced 132.5 g. of6-alpha-methylbenzylated-S-indanol, having a boiling point of 139 to 141C. at 0.4 mm. The 6-alphamethylbenzylated-S-indanol is a colorless oilwhich does not crystallize. Analysis of the end product confirms itschemical structure.

Evaluation of reaction products of examples I to IV (a) PREPARING TESTDUMBBELLS The eflicacy of the reaction products of Examples I to IVabove as flex-cracking resisters and heat stabilizers in vulcanizedrubber products is demonstrated by incorporating each such reactionproduct in a standard natural rubber tread stock recipe, curing in asteam press, and then testing. The tread stock recipe employed for thistest is:

Four rubber stocks, each compounded in accord with the above recipe andone containing each of the four reaction products of Examples I to IV,are compounded and cured. A blank stock, that is, one without adeterioration retarder, but otherwise the same as the above recipe,

8 and a control stock having 1 part of phenyl-beta-naphthyL aminereplacing the 1 part of the reaction product of the above recipe, arealso compounded and cured under like conditions for comparison purposes.a

(b) DETERMINING HEAT STABILITY AND FLEX-LIFE; AFTER AGING Each of thecompounded stocks referred to in the preceding paragraph is cured in aregulation steam press at 280 F. for 50 and minutes and then aged. Theaging follows the standard ASTM procedure (D865-48T). Test dumbbellstrips are cut from the vulcanized Stocks and aged in open test tubesfor 24 and 48 hours at 212 F. Some of these aged test strips aresubjected to stressstrain tests. Others of the aged test strips, whichare aged for 24 hours at 212 F., are subjected to flexing tests in theDeMattia Flexing Machine, where the test strips are flexed and thenumber of flexures automatically counted and recorded. The followingtest results are obtained:

Percentage of Original Tensile Strength Retained After Ag- Flex-Life ingat 212 F Test Dumbbells Improve- 24 Hrs. Aging 48 Hrs. Aging N o. ofmeat 50 80 50" 80 Flexes to Times Cure Cure Cure Cure Failure overBlank-mo deterioration retarder 56 46 32 31 30, 000 1. 0 Control-Phenyl-betanaphthylamine 78 64 55 49 132, 000 4. 4 Reaction Prodple I101 86 89 76 254, 000 B. 5 Reaction Prodple II 98 86 78 231, 000 7. 7Reaction Prodnet-Example III 101 96 87 252, 000 8. 4 ReactionProductExampie IV 98 88 91 240, 000 8. 0

From the above tabulation, it will be observed that. theheat-stabilizing properties of the reaction products of the Examples Ito IV are markedly superior to those ofthe blank and of thephenyl-beta-naphthylamine, one of the most Widely used antioxidants, andthe flex-life of the rub? ber tread stocks, compounded with the reactionproducts of Examples I to IV, is from 4 to 8 times longer than that ofthe blank stock and about 2 times longer than that of the stockcontaining phenyl-beta-napthylamine.

Applicant has found that alkylated indanols other than those hereinabovespecifically mentioned have comparable excellent heat-stabilizing andflexing-life properties. Some of these include 6-ethylated-5-indanol,4,6-diethylated-5- indanol, 5-ethylated-4-indanol,5,7-diethylated-4-indano1, 6-isopropylated-5-indanol,4,6-di-isopropylatd-S-indanol, 5-isopropylated-4-indanol,5,7-di-isopropylated-4-indanol, 6-t-butylated-5-indanol,4,6-di-t-butylated-S-indanol, S-tbutylated-4-indano1,5,7-di-t-butylated-4-indano1, 6-t-octylated-S-indanol,4,6-di-octylated-S-indanol, 5-t-octylated-4- indanol,5,7-di-octylated-4-indanol, and like alkylated indanols in which thealkylating olefins contain the hydrocarbon radical R" within the scopeabove noted; and also 9 1 1 ,3 -trimethyl-G-t-butylated-S-indanol,1,1,3-trimethyl-5-t-butylated-4-indanol,

and like higher homologues thereof, as well as1,3-dimethyl-6-alpha-methylbenzylated-S-indanol,1,3-dimethyl-5-alpha-methylbenzylated-4-indano1,1,l,3-trimethyl-6-alpha-methylbenzylated-S-indanol and the like.

Numerous other alkylated indanols have been prepared and tested asdeterioration retarders and have all shown on test to be excellentdeterioration retarders.

On the basis of the tests made, the generalization is warranted that thealkylation products of indanols and substituted indanols of thecharacter hereinabove described are as a class highly eifective asdeterioration retarders, and impart to vulcanized rubber remarkably highanti-flex-cracking and heat stabilizing properties, very eifectiveresistance to deterioration of tensile strength, elongation and otherdesirable properties, and are moreover non-staining and non-discoloringdeterioration retarders.

It is not the intention of the applicant to limit the invention of thisapplication to the specific disclosures herein set forth, which havebeen presented as illustrative, since modifications in the proportionsand the types of materials employed may be varied and equivalentmaterials may be employed, where desirable, without departing from thespirit or scope of this invention as defined in the appended claims.

What is claimed is:

1. A sulfur-vulcanized rubbery composition comprising a rubberydiolefinic polymer in which is dispersed from 0.3 to parts by weight onthe said polymer of a highly eifective heat stabilizing and superioranti-flexcracking deterioration retarder resulting from the chemicalreaction between an indanol and an alpha-olefin, the indanol being or"the general formula wherein R is a monovalent substituent selected fromthe class consisting of hydrogen and alkyl and aralkyl radicals havingfrom 1 to 8 carbon atoms, R is a monovalent substituent selected fromthe class consisting of hydrogen 10 and alkyl radicals having from 1 to8 carbon atoms, the alpha-olefin being of the general formula /RII HzC=CRI! wherein R" is a monovalent substituent selected from the classconsisting of hydrogen and alkyl and aralkyl radicals having from 1 to 8carbon atoms, the resulting reaction producing a deterioration retarderof the general formula wherein each R and R" is a monovalent substituentselected from the class consisting of hydrogen and alkyl and aralkylradicals having from 1 to 8 carbon atoms, R is a monovalent substituentselected from the class consisting of hydrogen and alkyl radicals havingfrom 1 to 8 carbon atoms, and n is an integer ranging from 1 to 2.

2. The sulfur'vulcanized rubbery composition defined in claim 1 whereinthe highly effective heat stabilizing and superior anti-flex-crackingdeterioration retarder comprises 6-t-butyl-5-indanol.

3. The sulfur-vulcanized rubbery composition defined in claim 1 whereinthe highly efiective heat stabilizing and superior anti-flex-crackingdeterioration retarder comprises 5-t-butyl-4-indano1.

4. The sulfur-vulcanized rubbery composition defined in claim 1 whereinthe highly effective heat stabilizing and superior anti-flex-crackingdeterioration retarder comprises 5,7-di-t-butyl-4-indanol.

5. The sulfur-vulcanized rubbery composition defined in claim 1 whereinthe highly effective heat stabilizing and superior anti-fiex-crackingdeterioration retarder comprises 4,6-di-t-bu-tyl-5-indanol.

6. The sulfur-vulcanized rubbery composition defined in claim 1 whereinthe highly effective heat stabilizing and superior anti-flex-crackingdeterioration retarder comprises 6-methylbenzyl-5-indanol.

References Cited in the file of this patent UNITED STATES PATENTS2,109,015 Niederl Feb. 22, 1938 2,198,374 Bruson Apr. 23, 1940 2,731,442Forman Jan. 17, 1956 2,731,443 Forman Jan. 17, 1956 2,754,285Petropouh's July 10, 1956 UNITED STATES PATENT OFFICE CERTIFICATION OFCORRECTION Patent No, 2 948 704 August 9 1960 Roger En Morris It ishereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1; line 55, for "on" read or column 2 lines 25 49 51 55 and 60,and column 3 lines 1 and 47, for Formula 1% each occurrence read meFormula (1) column 3 line 48 for "Formula 3" read me Formula (3) line 59for Formulas l and 3" read Formulas (l) and (3) v column 4 line 14 and30, for "Formula 4', each occurrence read me Formula (4) line 40 for"mula 4" read mula (4) column 5 line l7 for "groups" read em groupcolumn 7 lines to the left-hand portion of the formula should appear asshown below instead of as in the patent:

column 9,, lines to the formula should appear as shown below instead ofas in the patent:

Signed and sealed this 23rd day of May 1961o (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patems

1. A SULFUR-VULCANIZED RUBBER COMPOSITION COMPRISING A RUBBER DIOLEFINICPOLYMER IN WHICH IS DISPERSED FROM 0.3 TO 10 PARTS BY WEIGHT ON THE SAIDPOLYMER OF A HIGHLY EFFECTIVE HEAT STABILIZING AND SUPERIORANTI-FLEXCRACKING DETERIORATION RETARDER RESULTING FROM THE CHEMICALREACTION BETWEEN AN INDANOL AND AN ALPHA-OLEFIN, THE INDANOL BEING OFTHE GENERAL FORMULA